100-year-old whisky highlights art of blending

This file photo shows the crates of Mackinlay's Scotch whisky that were excavated from beneath British explorer Ernest Shackleton's hut in Antarctica.

Antarctica-bound explorers would be wise to bring a case or two of Scotch whisky to endure chilly nights. Ernest Shackleton was wise.

In fact, the Scotch he packed for the Nimrod's 1907 attempt to reach the South Pole was exceptional, according to distillers who sampled and re-created the drink.

Low on supplies and hungry, the expedition was forced to evacuate about 100 miles shy of its goal. When the crew departed Cape Royds, they left behind equipment and goods, including three cases of Mackinlay's "Rare Old Highland Malt Whisky" that was stashed in the ice beneath a hut.

In 2010, chemists and distillers with Whyte & MacLay, Ltd., which now owns Mackinlay's, got their hands on a few bottles and sampled a dram.

"The whisky had been in deep freeze ever since it was delivered to Antarctica," James Pryde, chief chemist at the distillery, recounted to me in an email. "We had no idea what we would find."

The hope was that given the cold storage coupled with a tight cork seal the whisky would be as good in 2010 as it was when it was blended more than a century earlier.

"This is what we found," Pryde said.

For aficionados of Scotch, that could be seen as backhanded compliment. Single malt whiskies from this period were generally regarded as "harsh and heavily peated," he noted - in other words, nothing to get excited about.

"Given we had no idea what we would find, it is not understatement that this dram turned out to be the 'nectar of the gods' — it was a revelation in its complexity, particularly the control of the peating level and the quality of the wood," Pryde said.

The storage under the hut while wrapped in straw and packed in wooden crates prevented the whisky from turning to ice and thus messing with the flavor profile. The preservation prompted an extensive analysis of the liquid.

"This as far as we know was the first analysis of a pristine whisky sample from the late 1800s and gave us real insight to what our forefathers were capable of when it came to whisky production," said Pryde.

The team determined the freezing point (-34.3 degrees C), alcoholic strength (47.19 percent), origin of the peat used in malting (Isle of Eday), and the nature of the wood casks used to mature it (American oak), for example.

The relatively high alcohol likely contributed to the lack of haze formation. "To have your whisky go cloudy would have been a PR disaster," noted Pryde.

The distillery had access to American oak casks used to transport sherry and wine and given its location near a port where this trade was particularly active, the distillery likely had the pick of the bunch.

All these aspects made for the exceptional blend for Shackleton and crew to sip, the team concludes in a paper detailing their analysis in the Journal of the Institute of Brewing.

To make it, Richard Pearson, master blender at Whyte & McKay Ltd., "used the best modern stocks of whisky that were at his disposal," noted Pryde. The blend was then subjected to the same scientific analysis as the original, confirming an almost identical match.

The lesson from the research project?

"I don't expect that any major changes will result from this work to the actual production of whisky," noted Pryde. But their findings do offer some sage advice for craft distillers of the future: master the art of blending.

"That is the most important thing that has been passed down from the 1900s."